1. Im also into bodybuilding and was doing a maximum arm size test that can guess how big your arms will be when you reach you peak in size. So a person with 7 inch wrists would be able to get his arms to 17 inches or so... Now is this going by a natural or a person on steroids? Can a person with 7 inch wrists break the 17inch max with steroids? and go continue on to 20-22 inch arms? Just curious.
(Also what body fat perentage are they talking about? One of my friends has 26 inch arms but hes fat as hell)

2. Second questions is, is it possible to have small joints but big bones? My friend has super small wrists but the rest of his body is big, hes not bulked up or anything pretty skinny but his bones are just plain bigger than mine, broader, thicker, but just his wrists are much smaller than mine. So that would mean the calculator is bs.

This may not be what you want to hear or a direct answer to your question, but I'll just say that if you're serious about getting into MMA, forget about the bodybuilding. It's next to useless in this sport.

Anyway, I'd say 6'1" isn't too short to be a heavyweight. But what's also important is reach. If you're not working with at least 76", you're definitely at a disadvantage.

Lesnar got dethroned by a guy who definitely does not have a bodybuilder's physique, and Overeem's currently serving a suspension for banned substances. Staying bulked up with useless muscle is definitely gonna hinder your performance.